1. Field of the Invention
The present invention relates to a super-absorbent polymer and a method of preparing the same.
2. Description of the Related Art
A super-absorbent polymer is a functional resin having an ability of absorbing water of several tens to thousands of times the weight of the polymer and keeping the same therein, and thus, is broadly used in various products including hygienic products such as a paper (disposable) diaper, sanitary goods, medical patches, agricultural absorbents, absorptive pads for foodstuffs, cable protective films, or the like.
The super-absorbent polymer is generally used in a powder form, and when it is applied to a product, it is usually used in combination with a fibrous substrate made of natural fiber such as non-woven fabric, pulp, etc. or synthetic fiber to form an absorbent material.
U.S. Pat. No. 6,914,099 discloses a method of preparing absorbent polymer particles based on cross-linked carboxyl containing polymer with a low monomer content, which includes polymerizing a polymer mixture including an ethylene unsaturated carboxyl containing monomer, a cross-linking agent, a comonomer copolymerisable with the carboxyl containing monomer, and a polymerization medium to form a cross-linked hydrogel.
However, since an internal cross-linking agent has higher reactivity than the carboxyl containing monomer, the internal cross-linking agent is exhausted at an initial stage of the reaction, or an acryl internal cross-linking agent has a low solubility in water used as a solvent to cause a difficulty in producing a uniform polymer composition, and therefore, it is hard to expect a uniform internal cross-linking structure.